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COMPRESSION OF BINARY FACSIMILE imageS BY PREprocessing AND COLOR SHRINKING

IEEE TRANSACTIONS ON COMMUNICATIONS 1990年第9期38卷 1592-1598页

作者： ALGAZI, VR KELLY, PL ESTES, RR Graphics Image and Vision Engineering Research Laboratory CIPIC Center for Image Processing Integrated Computing University of California Davis CA USA

Algorithms for preprocessing, global modeling and segmentation, local modeling and representation, and binary encoding of facsimile images are proposed, and their performance is examined. Some binary morphological operations that can be used to improve the quality and increase the compressibility of binary images and the modeling of binary images are discussed. The techniques are incorporated into a set of comprehensive encoding schemes, the PCSE codes. Their effectiveness in compressing the International Telegraphy and Telephony Consultative Committee (CCITT) binary images is demonstrated. The PCSE code using preprocessing and color shrinking prior to encoding is shown to outperform the READ code by from 7 to 42% for the standard CCITT test images with a very small change in image quality.< >

关键词： image coding Facsimile image segmentation Morphological operations Encoding Telegraphy Telephony Code standards Testing image quality

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Three-dimensional image analysis and display by space-scale matching of cross sections

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Journal of the Optical Society of America A: Optics and image Science, and vision 1989年第6期6卷 890-899页

作者： Algazi, V.R. Reutter, B.W. van Warmerdam, W.L.G. Liu, C.C. Graphics Image and Vision Engineering Research Laboratory Center for Image Processing and Integrated Computing University of California Davis CA 95616 United States

We present a framework and a set of techniques for the analysis and display of three-dimensional experimental data or images. We assume that the data are available in the form of two-dimensional cross sections of the three dimensional data set. We describe our approach, which has for goals to extract significant information from the three-dimensional data set and to display this information as objects that can be manipulated in three-dimensional space. The high-contrast transitions of two-dimensional cross sections are extracted first;they define a set of contours to be matched from cross section to cross section. This matching is performed by space-scale analysis of the orientation of contours on adjacent cross sections. By modeling the contours as B splines, we then make use of three-dimensional B-spline patches to generate significant surfaces that can be displayed, rendered, and rotated with standard computer graphics techniques and specialized processors. © 1989 Optical Society of America.

关键词： Computed tomography Computer simulation image analysis image processing Imaging systems Three dimensional imaging

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Morphological geodesic active contour based automatic aorta segmentation in thoracic CT images

Morphological geodesic active contour based automatic aorta ...

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International Conference on Computer vision and image processing, CVIP 2016

作者： Dasgupta, Avijit Mukhopadhyay, Sudipta Mehre, Shrikant A. Bhattacharyya, Parthasarathi Computer Vision and Image Processing Laboratory Department of Electronics and Electrical Communication Engineering Indian Institute of Technology Kharagpur West Bengal721302 India Institute of Pulmocare & Research KolkataWest Bengal700156 India

ISBN: (纸本)9789811021060

Automatic aorta segmentation and quantification in thoracic computed tomography (CT) images is important for detection and prevention of aortic diseases. This paper proposes an automatic aorta segmentation algorithm in both contrast and non-contrast CT images of thorax. The proposed algorithm first detects the slice containing the carina region. Circular Hough Transform (CHT) is applied on the detected slice to localize ascending and descending aorta (circles with lowest variances) followed by a morphological geodesic active contour to segment the aorta from CT stack. The dice similarity coefficients (DSC) between the ground truth and the segmented output were found to be 0.8845 ± 0.0584 on LIDC-IDRI dataset. © Springer Science+Business Media Singapore 2017.

关键词： image segmentation

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Colour Adjustment and Specular Removal for Non-uniform Shape from Shading

Colour Adjustment and Specular Removal for Non-uniform Shape...

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Proceedings of the Digital image Computing: Technqiues and Applications (DICTA)

作者： Xiaozheng Zhang Yongsheng Gao Terry Caelli Computer Vision and Image Processing Laboratory Griffith University Australia Biosecurity Group Queensland Research Laboratory NICTA Australia

Surface colour changes and specular reflections are two major problems in 3D modelling using shape-from-shading (SFS). This paper proposes to pre-process the input image for a typical SFS algorithm, so that the resultant image has no colour changes and specular reflection. First, a chromaticity-based specular reflection removal algorithm is applied to achieve a pure diffuse (Lambertian) reflected image. Then, a novel chromaticity-based colour adjustment approach is proposed to generate an image without surface colour changes. The standard SFS algorithms can then be applied successfully onto the processed images to produce plausible 3D models. In experiments, the proposed approach was tested on standard SFS datasets with complex surface colours. The experimental results show it's promising to facilitate SFS algorithms to handle SFS problems with more complex surface properties and illumination conditions.

关键词： image color analysis Reflection Pixel Shape Classification algorithms Surface treatment Lighting

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Width Distributions for Shape Description

Width Distributions for Shape Description

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Proceedings of the Digital image Computing: Technqiues and Applications (DICTA)

作者： Xiaozheng Zhang Yongsheng Gao Biosecurity Group Queensland Research Laboratory NICTA Australia Computer Vision and Image Processing Laboratory Griffith University Australia

Measuring the similarity between articulated shapes is a fundamental yet challenging problem. This paper proposes a novel shape descriptor based on Width Distributions (WD), which is robust to articulations. We show that the width distributions are articulation insensitive yet descriptive to distinguish different shapes with varied part structures. With measurements on distributions only, the proposed method does not require any alignment between two objects and thus is more robust than correspondence-based measurements. First, the medial axes of the objects are extracted and fitted to B-Splines to remove outliners. The width of the object shape perpendicular to the medial axis can be calculated for each position on the medial axis. The histograms of those widths are compared using chi-square method for similarity. Experiments on standard 2D shape database show that the proposed method performed better than standard shape distribution algorithms and similarly to other articulation-robust shape descriptors, such as inner-distance. The speed of the proposed method is much faster than the more sophisticated inner-distance, as the proposed method is much simpler in nature and requires limited image processing and pattern classification. These results suggested it could be an efficient and effective method to describe and to match articulated shapes.

关键词： Shape Histograms Robustness Databases Shape measurement Three dimensional displays Face

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Inspection Method of Track Facilities Using image Analysis of images Taken from Front of Trains

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Quarterly Report of RTRI (Railway Technical research Institute) 2023年第3期64卷 205-210页

作者： Nagamine, Nozomi Goda, Wataru Maeda, Riho Tsubokawa, Yosuke Kato, So Itoi, Kensuke Head of Image Analysis Laboratory Information and Communication Technology Division Research Areas: Computer Vision Image Processing Signalling Systems Japan Image Analysis Laboratory Information and Communication Technology Division Research Areas: Computer Vision Image Processing Japan Head of Track Geometry and Maintenance Laboratory Track Technology Division Research Areas: Track Measuring Japan Track Geometry and Maintenance Laboratory Track Technology Division Research Areas: Track Measuring Japan Research Areas: Track Measuring Japan

Appropriate maintenance of tracks is vital for the safe operation of railways. Properly managing track facilities is necessary to prevent buckling of rails. Changes in society are creating a shortage of workers, a decrease in skilled engineers, a decrease in passenger income, and an increase in the need to develop low-cost inspection methods which do not require experience. Therefore, we have developed a method using only inexpensive camcorders, which can extract information from images to detect joint gaps, wooden sleeper deterioration and ballast shape, and estimate the kilometer point of these images to locate the installations in question. This paper describes the outline of the method and its application results. © 2023 Ken-yusha Inc.. All rights reserved.

关键词： Inspection

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Motion constraint patterns

Motion constraint patterns

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1993 IEEE Workshop on Qualitative vision, WQV 1993

作者： Fermüller, Cornelia Computer Vision Laboratory Center for Automation Research University of Maryland College ParkMD20742-3275 United States Department for Pattern Recognition and Image Processing Institute for Automation Technical University Vienna Treitlstraße 3 ViennaA-1040 Austria

ISBN: (纸本)0818636920

The problem of egomotion recovery has been treated by using as input local image motion, with the published algorithms utilizing the geometric constraint relating 2-D local image motion (optical flow, correspondence, derivatives of the image flow) to 3-D motion and structure. Since it has proved very difficult to achieve accurate input (local image motion), a lot of effort has been devoted to the development of robust techniques. A new approach to the problem of egomotion estimation is taken, based on constraints of a global nature. It is proved that local normal flow measurements form global patterns in the image plane. The position of these patterns is related to the three dimensional motion parameters. By locating some of these patterns, which depend only on subsets of the motion parameters, through a simple search technique, the 3-D motion parameters can be found. The proposed algorithmic procedure is very robust, since it is not affected by small perturbations in the normal flow measurements. As a matter of fact, since only the sign of the normal flow measurement is employed, the direction of translation and the axis of rotation can be estimated with up to 100% error in the image measurements. © 1993 IEEE.

关键词： Flow measurement

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Multi-Scale Saliency-Guided Compressive Sensing Approach to Efficient Robotic Laser Range Measurements

Multi-Scale Saliency-Guided Compressive Sensing Approach to ...

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Canadian Conference on Computer and Robot vision, CRV

作者： Shimon Schwartz Alexander Wong David A. Clausi Department of Systems Design Engineering Vision and Image Processing Laboratory research group University of Waterloo Waterloo ONT Canada

Improving laser range data acquisition speed is important for many robotic applications such as mapping and localization. One approach to reducing acquisition time is to acquire laser range data through a dynamically small subset of measurement locations. The reconstruction can then be performed based on the concept of compressed sensing (CS), where a sparse signal representation allows for signal reconstruction at sub-Nyquist measurements. Motivated by this, a novel multi-scale saliency-guided CS-based algorithm is proposed for an efficient robotic laser range data acquisition for robotic vision. The proposed system samples the objects of interest through an optimized probability density function derived based on multi-scale saliency rather than the uniform random distribution used in traditional CS systems. Experimental results with laser range data from indoor and outdoor environments show that the proposed approach requires less than half the samples needed by existing CS-based approaches while maintaining the same reconstruction performance. In addition, the proposed method offers significant improvement in reconstruction SNR compared to current CS-based approaches.

关键词： Measurement by laser beam image reconstruction image coding Robot sensing systems Noise measurement Signal to noise ratio

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Maximum likelihood thresholding algorithm based on four-parameter gamma distributions

Maximum likelihood thresholding algorithm based on four-para...

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International Conference on Electrical Engineering, Computing Science and Automatic Control (CCE)

作者： Peter De-Ford Geovanni Martinez Image Processing and Computer Vision Research Laboratory (IPCV-LAB) Universidad de Costa Rica San José Costa Rica

In this contribution, we present a segmentation algorithm based on thresholding to subdivide an intensity image in the regions of object and background. The optimal threshold is found by maximizing a likelihood function derived from a novel intensity probability density function model, which consists of the sum of two weighted four-parameter gamma distributions, as a more flexible alternative to currently used models consisting of the sum of two weighted two-parameter Gaussian distributions. According to our experiments with 132 images, the proposed algorithm is in average slightly better than the best found in the scientific literature, performing particularly good in low contrast images. The additional parameters and complexity of its likelihood function resulted in an increase of the processing time by a factor of 3, from 0.003 sec/image to 0.009 sec/image.

关键词： image segmentation Probability density function Approximation algorithms Gaussian distribution Histograms Shape Pattern recognition

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Varying pose face recognition using combination of discrete cosine & wavelet transforms

Varying pose face recognition using combination of discrete ...

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International Conference on Intelligent and Advanced Systems, ICIAS

作者： Seyed Omid Shahdi S. A. R. Abu-Bakar Computer Vision Video and Image Processing (CvviP) Research Laboratory Faculty of Electrical Engineering Universiti Teknologi Malaysia Skudai Johor Malaysia

Requirement for a person to face a camera for face identification process may no longer be necessary if the face recognition system is robust against variation of facial pose. In this paper, we proposed a face recognition method which remains reliable even in very large head pose variations. In this method, feature from local regions of face are extracted after employing both discrete cosine transform and discrete wavelet transform. Learning strategy is then applied to infer the relationship between face in a given pose and its frontal view. Results we obtained are very promising considering that our proposed method solely relies on a single gallery image. We also demonstrated the high performance of our method in a condition whereby the face images are of low-resolution quality.

关键词： Face Face recognition Vectors Discrete cosine transforms Discrete wavelet transforms Feature extraction Databases

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